Salient information is processed by a subcortical mesolimbic dopaminergic circuit comprising the amygdala, ventral striatum and orbitofrontal cortex . Symptoms of Attention Deficit/Hyperactivity Disorder (ADHD) include distractibility that suggests more attention to salient but task irrelevant information in the environment. Salient information refers to stimuli that spontaneously capture attention such as perceptually novel, infrequent, or unique because they are emotional. The proposed studies examine involuntary attention to emotional stimuli in 9-13 year old ADHD and age and IQ-matched control children. The primary goal of the proposed research is to test the hypothesis that emotionally salient stimuli capture attention to a greater extent in ADHD than control children due to a hyper-activated amygdala. This hypothesis is consistent with problems of emotional regulation that are widely reported but less investigated in ADHD research. Results of this study will contribute to a greater understanding of the neurobiology of ADHD and begin to probe the importance of assessing individual differences in a heterogeneous clinical population. This proposed research will also be important later in addressing the dopaminergic influences on salience processing among children with ADHD. The proposed experiment will be among the first to investigate both the behavior and the neural basis of encoding emotionally salient information (Specific Aims 1 & 2). The amygdala has been shown in normal adults and children to play a role in involuntary attention to emotion. Unfortunately the role of the amygdala has not been well understood or characterized in ADHD despite neural evidence of mesolimbic dysfunction and behavioral evidence of emotional dysregulation. In addition, the proposed experiment will also continue to address the heterogeneity in ADHD symptoms by looking at individual differences in anxiety (Specific Aim 3). One of the problems that has plagued ADHD research is the issue of comorbid disorders like anxiety, thus it is now necessary to begin investigating how comorbidities might influence attentional processes, (here in this experiment it would be processing of emotionally salient information). Results from this study are relevant to understanding one of the most common psychiatric disorders of childhood, ADHD. It is important to understand what captures the attention of a child with ADHD in order to develop better treatments and apply appropriate strategies in the home and school environments. Also by identifying how and where in the brain children with ADHD process emotionally salient information, it may be possible to discover a mechanism for the mesolimbic dysfunction and emotional dysregulation seen in ADHD. [unreadable] [unreadable] [unreadable]